Polymer Soft Actuators Research Articles

Self-standing bacterial cellulose-reinforced poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) doped with graphene oxide composite electrodes for high-performance ionic electroactive soft actuators.

Flexible electrode films with good film-forming properties, large deformation ability, high conductivity, and strong charge and discharge capabilities are crucial for ionic electroactive polymer soft actuators. However, there are still challenges in preparing high-quality electrode films that can combine well with the intermediate polyelectrolyte to form high-performance soft actuators. Herein, we propose an advanced sandwich ionic electroactive actuator utilizing self-standing bacterial cellulose (BC) reinforced poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PP) doped with graphene oxide (GO) conductive composite electrodes and a Nafion ion-exchange membrane via a hot-pressing method. The prepared BC-PP-GO electrodes have good film-forming properties with a Young's modulus of 1360 MPa and a high conductivity of 150 S cm-1. The hot-pressed BC-PP-GO/Nafion ionic actuator exhibited a large bending displacement of 6.2 mm (1 V, 0.1 Hz) with a long-term actuation stability up to 95% over 360 cycles without degradation. Furthermore, we introduced the actuator's potential applications including bionic grippers, flies, and fish, providing more opportunities for the development of next-generation micromanipulators and biomimetic microrobots in cm-scale space.

Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

Application and Analysis of an Ionic Liquid Gel in a Soft Robot

Due to their light weight, flexibility, and low energy consumption, ionic electroactive polymers have become a hotspot for bionic soft robotics and are ideal materials for the preparation of soft actuators. Because the traditional ionic electroactive polymers, such as ionic polymer-metal composites (IPMCs), contain water ions, a soft actuator does not work properly upon the evaporation of water ions. An ionic liquid polymer gel is a new type of ionic electroactive polymer that does not contain water ions, and ionic liquids are more thermally and electrochemically stable than water. These liquids, with a low melting point and a high ionic conductivity, can be used in ionic electroactive polymer soft actuators. An ionic liquid gel (ILG), a new type of soft actuator material, was obtained by mixing 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), hydroxyethyl methacrylate (HEMA), diethoxyacetophenone (DEAP) and ZrO2 and then polymerizing this mixture into a gel state under ultraviolet (UV) light irradiation. An ILG soft actuator was designed, the material preparation principle was expounded, and the design method of the soft robot mechanism was discussed. Based on nonlinear finite element theory, the deformation mechanism of the ILG actuator was deeply analyzed and the deformation of the soft robot when grabbing an object was also analyzed. A soft robot was designed with the soft actuator as the basic module. The experimental results show that the ILG soft robot has good driving performance, and the soft robot can grab a 105 mg object at an input voltage of 3.5 V.

A Highly Stretchable Tough Polymer Actuator Driven by Acetone Vapors

AbstractStimuli‐responsive polymer materials having high stretchability and robust toughness are more promising for applications in wearable electronics, soft robotics, and sensors. Herein, a micropatterned single‐layered polymer soft actuator is reported that can be stretched to 600% of its original length with the strength reaching 40 MPa. The prominent mechanical stretchability comes from the modification of poly(vinylidene fluoride) (PVDF) by using 3‐methacryloxypropyltrimethoxysilane (MS), followed by the treatment with mechanical uniaxial stretching. The uniaxial stretching induces microscopic patterning of the PVDF/MS composite actuator, making it capable of kinematics‐controllable movements in response to acetone vapors. The mechanically strong single‐layered vaporesponsive PVDF/MS actuator overcomes many drawbacks of polymer bilayer actuators that might undergo interfacial failure and inactivation caused by less‐than‐perfect mechanical properties. Driven by acetone vapors, the PVDF/MS actuator demonstrates highly efficient energy conversion and sensing abilities with simulating artificial muscles for inducing the movements of various paper dolls.

Modeling, fabrication, and characterization of motion platform actuated by carbon polymer soft actuator

Carbon polymer composites (CPC) are kind of soft actuators belonging to the category of ionic electroactive polymer transducers. In this work, we present design, modeling, fabrication, and characterization of a novel parallel manipulation system actuated by the CPC actuators. In this system, four actuators are operated in parallel to manipulate an end effector or a platform to generate motion along the different axis. The major advantage of the current system is that the platform and the actuators are fabricated as a single structure using the simple layer-by-layer spray-deposition method with selective masking. The proposed system is highly dexterous and is capable of generating three degrees of motions, namely, roll, pitch, and piston. The initial structural design and its deformation are optimized by modeling and simulating using finite element method and followed by fabrication and characterization to examine its workspace. The experimental results have demonstrated high levels of manipulability from the CPC actuators that are outstanding in the class of soft ionic actuators while keeping the fabrication method simple, scalable and cost-effective. The proposed configuration has potential application in micromanipulation systems that require large deformation in a confined space.

Modelling and Control of Ionic Electroactive Polymer Actuators under Varying Humidity Conditions

In this work, we address the problem of position control of ionic electroactive polymer soft actuators under varying relative humidity conditions. The impact of humidity on the actuation performance of ionic actuators is studied through frequency response and impedance spectroscopy analysis. Considering the uncertain performance of the actuator under varying humidity conditions, an adaptable model using the neural network method is developed. The model uses relative humidity magnitude as one of the model parameters, making it robust to different environmental conditions. Utilizing the model, a closed-loop controller based on the model predictive controller is developed for position control of the actuator. The developed model and controller are experimentally verified and found to be capable of predicting and controlling the actuators with excellent tracking accuracy under relative humidity conditions varying in the range of 10–90%.

Effect of porosity and tortuosity of electrodes on carbon polymer soft actuators

This work presents an electro-mechanical model and simulation of ionic electroactive polymer soft actuators with a porous carbon electrode, polymer membrane, and ionic liquid electrolyte. An attempt is made to understand the effects of specific properties of the porous electrodes such as porosity and tortuosity on the charge dynamics and mechanical performance of the actuator. The model uses porous electrode theory to study the electrochemical response of the system. The mechanical response of the whole laminate is attributed to the evolution of local stresses caused by diffusion of ions (diffusion-induced stresses or chemical stresses). The model indicates that in actuators with porous electrode, the diffusion coefficient of ions, conductivity of the electrodes, and ionic conductivity in both electrodes and separator are altered significantly. In addition, the model leads to an obvious deduction that the ions that are highly active in terms of mobility will dominate the whole system in terms of resulting mechanical deformation direction and rate of deformation. Finally, to validate the model, simulations are conducted using the finite element method, and the outcomes are compared with the experimental data. Significant effort has been put forward to experimentally measure the key parameters essential for the validation of the model. The results show that the model developed is able to well predict the behavior of the actuator, providing a comprehensive understanding of charge dynamics in ionic polymer actuator with porous electrodes.

Electrode Effects on Polyurethane Soft Actuator

A polymer soft actuator is under investigation using a poly urethane elastomer film that bends by means of an applied voltage, which is based on the electrostriction. Bending experiments were performed under different metal electrodes deposited the both sides of the film. Even if the thickness of the both electrodes is the same, the metal of the both electrodes is desirable to be the same to bend more. It is suggested that the balance of the physical properties of the both metal is critical for larger bending.

Response to Applied Voltage to Polyurethane Soft Actuators with Loaded Weights

We are investigating a polymer soft actuator using a poly urethane elastomer film that bends by an applied voltage, which is based on the electrostriction. In this article, the bending magnitude was studied in a weight-loaded condition. It was found that the thinner film can bend the more without any load, but that the film of 200-μm thickness gave the largest bending when weights were loaded. The thickness of some degree is critical for large bending torque.

Research Trends of Soft Actuators based on Electroactive Polymers and Conducting Polymers

Artificial muscles (or soft actuators) based on electroactive polymers (EAPs) are attractive power sources to drive human-like robots in place of electrical motor, because they are quiet, powerful, light weight and compact. Among EAPs for soft actuators, conducting polymers are superior in strain, stress, deformation form and driving voltage compared with the other EAPs. In this paper, the research trends of EAPs and conducting polymers are reviewed by retrieval of the papers and patents. The research activity of EAP actuators showed the maximum around 2010 and somehow declining now days. The reasons for the reducing activity are found to be partly due to problems of conducting polymer actuators for the practical application. The unique characteristics of conducting polymer actuators are mentioned in terms of the basic mechanisms of actuation, creeping, training effect and shape retention under high tensile loads. The issues and limitation of conducting polymer soft actuators are discussed.

Application of Conducting Polymer Soft Actuator to Control Equipments

Application of Conducting Polymer Soft Actuator to Control Equipments

Development Trend of Electrically Conducting Polymer Soft Actuators

Development Trend of Electrically Conducting Polymer Soft Actuators

導電性高分子ソフトアクチュエータを駆動源とするマイクロポンプ

導電性高分子ソフトアクチュエータを駆動源とするマイクロポンプ

A micropump driven by a polypyrrole‐based conducting polymer soft actuator

AbstractMicropumps are essential components of microfluidic systems and biosensing systems. In particular, micropumps used for micro total analysis systems transport fluids at a microflow rate with high precision. Moreover, they are also needed to transport high‐viscosity fluids in cases where there are various types of drugs to be transported. Therefore, in order to realize a micropump that can transport solutions at a microflow rate, it is necessary to develop a high‐precision microdeformable actuator with a simple mechanism. The conducting polymer soft actuator reported here opens widely and closes completely as a result of electrochemical oxidation and reduction, respectively. The opening and closing movement of the soft actuator, inside which the cation‐driven layer is arranged, becomes large because the anion‐driven layer that is arranged outside is the predominant driver. We developed a micropump driven by a conducting polymer soft actuator that opens and closes. Although the developed micropump contains no valve, the micropump can transport fluids in one direction without backflow. The newly developed micropump driven by the conducting polymer soft actuator can transport fluids in one direction without backflow by the opening and closing of two soft actuators. Furthermore, a wider range of flow rates and greater maximum delivery heads are obtained using the newly developed micropump. The energy consumption rate of the micropump is markedly lower than those of conventional micropumps. Copyright © 2010 Society of Chemical Industry

Performance of a Micro Pump Driven by Conducting Polymer Soft Actuator Based on Polypyrrole

Micro pumps are essential components of micro-fluidic systems and bio-sensing systems. In particular, the micro pump used for -TAS transports fluids at a micro flow rate with high precision. This micro pump is also used to transport high-viscosity fluids because there are various types of drugs to be transported. We developed a micro pump driven by a conducting polymer soft actuator that opens and closes. Although the developed micro pump contains no valve, the micro pump can transport fluids in one direction without backflow. A newly developed micro pump driven by a conducting polymer soft actuator can transport fluids in one direction without backflow by the opening and closing of two soft actuators.

Conducting polymer soft actuators based on polypyrrole films—energy conversionefficiency

The electrochemomechanical deformation (ECMD) of conducting polymers can be usedto create soft actuators or transducers for the conversion of electric power tomechanical work. Polypyrrole (PPy) films, which were electrodeposited from amethyl benzoate solution of tetrabutylammonium (TBA) trifluoromethansulfonate,TBACF3SO3, were used to investigate the energy conversion efficiency. The films are known to havehigh tensile strength and to produce large strain at high stress in ECMD. The current asa function of load stress under constant applied potentials versus a referenceelectrode was studied in various electrolytes. Reduction currents increased withincreasing load stress for contraction of the film (lifting weights) as well as for theoxidation current (expansion), indicating that the electrical input was sensing theload hung on the actuators. During the contraction, the conversion efficiency wasestimated from the mechanical work energy. The maximum work energy-per-cycle was140 kJ m−3. It has been found that the energy conversion efficiencies are very small(<0.25%). Most of the input electrical energy is stored electrochemically, but a significant fraction isalso dissipated.

1107 導電性高分子による開閉運動アクチュエータを駆動源としたマイクロポンプの基礎特性(2)(OS11-2 ナノ・マイクロフルイディクス(マイクロポンプ・センサー),OS11 ナノ・マイクロフルイディクス,オーガナイズドセッション)

Various micro pumps are developed recent years. We have proposed a soft actuator that performs open-close movement and micro pump using soft actuator as a driving source. We have developed an soft actuator that perform open-close movement by arranging an soft actuator in which bimorph structures with anion-driven layers and cation-driven layers are connected and cation-driven layers arranged in face to-face relation. The authors have built up a micro-pump with the conducting polymer soft actuator that performs open-close movement as a driving source. Its oscillation volume can be adjusted in the range of 4〜47[μl/min]. Moreover, micro pump which used two actuators can transport flow in the range of 4〜39[μl/min].This micro pump which authors developed can work by low energy consumption.